This invention relates to users that are not directly coupled to an internet protocol (IP) multimedia subsystem (IMS) such as users coupled to an IMS by a private branch exchange (PBX). More specifically the invention relates to the registration of such users as subscribers of the IMS even though such users are coupled through an endpoint to the IMS. The endpoints may be a PBX, a key system or potentially a line gateway or other “line aggregator” system. Since the PBX is a common model, it is used as the example in the embodiment described below.
Advances in telephony communications provide benefits for users but sometimes present difficulties which must be overcome by telecommunication service providers. Examples of such difficulties reside in the challenges associated with the use of new equipment utilizing new technology with existing telecommunications infrastructure equipment, and challenges associated with the use of new telecommunications infrastructure equipment utilizing new technology with existing equipment. In order to take advantage of the benefits associated with integrating devices using newer technology with existing devices, compatibility and interoperability problems between devices utilizing the new technology and devices utilizing existing technology must be overcome.
Voice over internet protocol (VOIP) telephony services continue to grow. Consumers with high-speed data connections such as supported by DSL, cable modem or fiber optic lines can elect to have telephony services provided using VOIP technology over such connections. This provides an alternative to the telephony services historically provided to users by telephone companies over dedicated telephone wires. Users served by a PBX system enabled with packet based technology such as VOIP or time division multiplex (TDM) technologies benefit from the use of such technology. Although existing packet based PBX systems provide telephony services between its users and the PBX itself, existing PBX systems may not provide a mechanism whereby its users can become registered as VOIP subscribers in systems outside of the PBX. For example, users of such a VOIP PBX system are unable to take advantage of services provided by an IMS to which the VOIP PBX system is connected because the VOIP PBX does not provide a mechanism such as authentication and service-routing that are required for the PBX users to become registered VOIP subscribers of the IMS. Some services offered by the IMS are made available only to subscribers that are registered with the IMS. This prevents users of such a PBX from obtaining telecommunications services provided via the IMS where registration with the IMS is a prerequisite. There is a need for solution to this problem.